"Create your own masterpiece" from "quality" patties and a "veritable plethora" of "gourmet" toppings at this "custom burger" chain, where the "happy" staffers also serve up "habit-forming" fries, thick shakes and "interesting" craft brews; critics counter they're "stark", "clamorous" and "pricey", but the "casual" approach that's "fun for kids" is "a hit."